In the rapid development of the computer arts, the capacities of the computer to handle data has greatly increased. However the manual input of data through keyboards has continued to be a significant limitation to the high speed data processing capabilities available. Also there are so many possible functions performed by modern computers, that there is a limitation on the use of many of them in the keyboard manual input restrictions of the prior art. Even pocket sized portable computers have hundreds of data and command functions otherwise accessible to keyboard operation unavailable because of keyboard limitations.
The trend to computer keyboard operation is evidenced by the C. Tung, U.S. Pat. No. 3,892,958 July 1, 1975, which requires 36 keyboard keys to access at most about 100 computer functions, thereby using only a small part of those that could be made available. This keyboard uses two of the 36 keys for changing the key assignments from a default mode to two other modes thereby tripling the number of accessible data input characters and operating commands otherwise available from the 36 keys. Each key thus produces from a single keystroke a different function in each of the modes. Thus to increase the number of functions above about 100 in this conventional prior art manner, either the number of keys must be increased or the number of key assignment modes must be increased.
It is extremely difficult to enter any substantial variety of information into the computer, with such keyboards, including the provision of alphabetic characters, which with 26 entries required necessitates separate modes for numeric digits or computer command signals and alpha characters from the 36 key keyboard. Futhermore, if this computer is used in the programming mode for example, very complex keystroke sequences are involved, such as changing from mode to mode by use of the mode change keys many times in the entry of a program step. This of itself is not conducive to fast entry touch typing. Furthermore the key layout is not capable of easy entry by touch typing, and is primarily only useful for slow hunt and peck methods.
In other conventional computer input keyboards such as for personal computers, QWERTY typewriter keyboards are supplemented with further sets of keys, typically about 40. It is impossible to efficiently use such keyboards for rapid touch typing input because of the necessity to reach to many inconvenient positions for command signals. Also it is conventional for each command signal to use one key, so that most of the available capacity of the computer to access functions and subroutines simply is sacrificed in favor of complex routines using many keystrokes and much waiting time.
It is therefore a primary object of this invention to produce rapid manual entry of input data and commands into a data processing computer system from a keyboard, capable of rapid touch typing and having the capability to process a greater proportion of the accessible computer functions with simple keystrokes.
It is known in the art to reduce the number of keyboard keys required for a given number of entries, by making entries of individual data characters or control commands in response to two successive keystrokes. Thus, a set of keys may produce more than one input entry per key. If n keys are available, n times n entries may be provided by two strokes per character operation, n times n times n entries may be provided by three stroke per character operation, etc.
Thus in British Patent No. 1,417,849, Dec. 17, 1975 with two strokes per character, operation of a typewriter is permitted by means of only seven keys. U.S. Pat. No. 3,833,765 issued to E. hillborn et al. Sept. 3, 1974 provides for both alphabet characters and more complex messages to be chosen by the two letter codes provided by the two successive keystrokes from a set of twelve keys arranged for four finger touch typing with one hand. U.S. Pat. No. 3,967,273 issued to K. Knowlton on June 29, 1976 provides for the two keystroke per character entry operation from a telephone keyboard to permit both alphabetic and numeric digits to be generated from twelve keys.
It is one feature of the invention that this type of two (or more) strokes per character keyboard in data processing systems will reduce the number of keys required and significantly increase the number of computer functions accessible by the keyboard. Thus, with only twelve keys, more selections may be made in a two stroke per character mode than with the 36 keys of the aforementioned Tung keyboard.
No known computer-keyboard art has been provided that is convenient and fast for manual manipulation in the touch typing mode for both data and command input entries, or for large numbers of entries with few keys. Thus, it is a particular system objective to provide a touch typing keyborad input capability with a few keys efficiently operable by the fingers of a single hand or entry of a large number of both data and command signals to a computerized data processing system.
Also it is an object of this invention to provide improved keyboards having few keys and operable in fast typing modes from touch typing from the fingers of one hand for replacing conventional typewriter keyboards.
It has been found in computer keyboards requiring two or more successive keystrokes per entry adapted for high speed touch typing that typing speeds can approximate those customary in conventional typewriters after operators learn the alphabet and practice the two stroke per entry mode of operation.
However a problem is introduced with the two (or more) stroke per entry mode of operation that could result in unintelligible text following an operator error. Thus, if one stroke of a two-stroke sequence is missed by the operator in a typing sequence without the operator's recognition and correction, the following text will become unintelligible, because the operator continues to stroke in a two stroke per entry mode with the two strokes out of synchronization with the entry of the data into the computer.
Accordingly an explicit objective of this invention is to produce a solution to that problem.